kudri

The tool comes free, and that is the point of meeting this verb here. Kudri is to sew. Add the tool suffix -il- and you get kudrilo, a needle, which is the word most learners reach for first and cannot build until they have the verb underneath it. The najlo page had to explain that najlo looks like an -il- build and is not one, because there is no verb naji. Here the machine actually runs: kudri is a real verb, so kudrilo is a real derivation, and the pattern is the same one that turns tondi into tondilo, a pair of scissors.

The rest of the family costs nothing either. Kudrado is sewing as an activity, kudraĵo is a piece of needlework, kudrero is a single stitch, kudristo is a tailor or a seamstress, and kudromaŝino is a sewing machine. Alkudri is to sew something on, which is what the button sentence above is doing, and diskudri is to unpick. Six words from one root and three affixes you already know.

Do not confuse it with tondi. Both live in the same drawer, and the difference is direction: tondi cuts the cloth apart and kudri puts it back together. A tailor does both, in that order, and so their two tools, tondilo and kudrilo, are built by exactly the same suffix from exactly the same shape of verb. Learn one build and you have the other.